---

2.
char (*abc)[100];

---

Rewrite it with all parentheses explicitly shown:
char ((*abc)[100]);
and read it from the inside out:

1. abc is being declared,
2. it is a pointer to something,
3. the something is an array of 100 somethings,
4. they are characters.

So abc is a pointer to an array of 100 characters.
         but
Read the note attached to number 3.

---

A pointer usually requires 4 bytes, so (sizeof abc) is 4.

---